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Hazuda DJ, Felock P, Witmer M, Wolfe A, Stillmock K, Grobler JA, Espeseth A, Gabryelski L, Schleif W, Blau C, Miller MD. Inhibitors of strand transfer that prevent integration and inhibit HIV-1 replication in cells. Science 2000; 287:646-50. [PMID: 10649997 DOI: 10.1126/science.287.5453.646] [Citation(s) in RCA: 884] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Integrase is essential for human immunodeficiency virus-type 1 (HIV-1) replication; however, potent inhibition of the isolated enzyme in biochemical assays has not readily translated into antiviral activity in a manner consistent with inhibition of integration. In this report, we describe diketo acid inhibitors of HIV-1 integrase that manifest antiviral activity as a consequence of their effect on integration. The antiviral activity of these compounds is due exclusively to inhibition of one of the two catalytic functions of integrase, strand transfer.
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Kushnareva Y, Murphy AN, Andreyev A. Complex I-mediated reactive oxygen species generation: modulation by cytochrome c and NAD(P)+ oxidation-reduction state. Biochem J 2002; 368:545-53. [PMID: 12180906 PMCID: PMC1222999 DOI: 10.1042/bj20021121] [Citation(s) in RCA: 515] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2002] [Accepted: 08/15/2002] [Indexed: 02/07/2023]
Abstract
Several lines of evidence indicate that mitochondrial reactive oxygen species (ROS) generation is the major source of oxidative stress in the cell. It has been shown that ROS production accompanies cytochrome c release in different apoptotic paradigms, but the site(s) of ROS production remain obscure. In the current study, we demonstrate that loss of cytochrome c by mitochondria oxidizing NAD(+)-linked substrates results in a dramatic increase of ROS production and respiratory inhibition. This increased ROS production can be mimicked by rotenone, a complex I inhibitor, as well as other chemical inhibitors of electron flow that act further downstream in the electron transport chain. The effects of cytochrome c depletion from mitoplasts on ROS production and respiration are reversible upon addition of exogenous cytochrome c. Thus in these models of mitochondrial injury, a primary site of ROS generation in both brain and heart mitochondria is proximal to the rotenone inhibitory site, rather than in complex III. ROS production at complex I is critically dependent upon a highly reduced state of the mitochondrial NAD(P)(+) pool and is achieved upon nearly complete inhibition of the respiratory chain. Redox clamp experiments using the acetoacetate/L-beta-hydroxybutyrate couple in the presence of a maximally inhibitory rotenone concentration suggest that the site is approx. 50 mV more electronegative than the NADH/NAD(+) couple. In the absence of inhibitors, this highly reduced state of mitochondria can be induced by reverse electron flow from succinate to NAD(+), accounting for profound ROS production in the presence of succinate. These results lead us to propose a model of thermodynamic control of mitochondrial ROS production which suggests that the ROS-generating site of complex I is the Fe-S centre N-1a.
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Costantini P, Chernyak BV, Petronilli V, Bernardi P. Modulation of the mitochondrial permeability transition pore by pyridine nucleotides and dithiol oxidation at two separate sites. J Biol Chem 1996; 271:6746-51. [PMID: 8636095 DOI: 10.1074/jbc.271.12.6746] [Citation(s) in RCA: 398] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
After accumulation of a Ca2+ load, the addition of uncoupler to respiring rat liver mitochondria is followed by opening of the permeability transition pore (MTP), a voltage-dependent channel sensitive to cyclosporin A. The channel's voltage threshold is profoundly affected under conditions of oxidative stress, with a shift to more negative values that may cause MTP opening at physiological membrane potentials. In this paper we further clarify the mechanisms by which oxidative agents affect the apparent voltage dependence of the MTP. We show that two sites can be experimentally distinguished. (i) A first site is in apparent oxidation-reduction equilibrium with the pyridine nucleotide (PN) pool (NADH/NAD + NADPH/NADP); PN oxidation is matched by increased MTP open probability under conditions where the glutathione pool is kept in the fully reduced state; this site can be blocked by N-ethylmaleimide but not by monobromobimane, a thiol-selective reagent. (ii) A second site coincides with the oxidation-reduction-sensitive dithiol we have recently identified (Petronilli, V., Costantini, P., Scorrano, L., Colonna, R., Passamonti, S., and Bernardi, P. (1994) J. Biol. Chem. 269, 16638-16642); dithiol cross-linking at this site by arsenite or phenylarsine oxide is matched by increased MTP open probability under conditions where the PN pool is kept in the fully reduced state; at variance from the first, this site can be blocked by both N-ethylmaleimide and monobromobimane and is probably in equilibrium with the glutathione pool. Based on these findings, we reassess the mechanisms by which many oxidative agents affect the MTP and resolve conflicting reports on the relative role of PN and glutathione oxidation in the permeability transition within the framework of MTP (dys)regulation at two separate sites.
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Maalouf M, Sullivan PG, Davis L, Kim DY, Rho JM. Ketones inhibit mitochondrial production of reactive oxygen species production following glutamate excitotoxicity by increasing NADH oxidation. Neuroscience 2007; 145:256-64. [PMID: 17240074 PMCID: PMC1865572 DOI: 10.1016/j.neuroscience.2006.11.065] [Citation(s) in RCA: 339] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Revised: 11/09/2006] [Accepted: 11/28/2006] [Indexed: 12/27/2022]
Abstract
Dietary protocols that increase serum levels of ketones, such as calorie restriction and the ketogenic diet, offer robust protection against a multitude of acute and chronic neurological diseases. The underlying mechanisms, however, remain unclear. Previous studies have suggested that the ketogenic diet may reduce free radical levels in the brain. Thus, one possibility is that ketones may mediate neuroprotection through antioxidant activity. In the present study, we examined the effects of the ketones beta-hydroxybutyrate and acetoacetate on acutely dissociated rat neocortical neurons subjected to glutamate excitotoxicity using cellular electrophysiological and single-cell fluorescence imaging techniques. Further, we explored the effects of ketones on acutely isolated mitochondria exposed to high levels of calcium. A combination of beta-hydroxybutyrate and acetoacetate (1 mM each) decreased neuronal death and prevented changes in neuronal membrane properties induced by 10 microM glutamate. Ketones also significantly decreased mitochondrial production of reactive oxygen species and the associated excitotoxic changes by increasing NADH oxidation in the mitochondrial respiratory chain, but did not affect levels of the endogenous antioxidant glutathione. In conclusion, we demonstrate that ketones reduce glutamate-induced free radical formation by increasing the NAD+/NADH ratio and enhancing mitochondrial respiration in neocortical neurons. This mechanism may, in part, contribute to the neuroprotective activity of ketones by restoring normal bioenergetic function in the face of oxidative stress.
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Research Support, Non-U.S. Gov't |
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Juge N, Gray JA, Omote H, Miyaji T, Inoue T, Hara C, Uneyama H, Edwards RH, Nicoll RA, Moriyama Y. Metabolic control of vesicular glutamate transport and release. Neuron 2010; 68:99-112. [PMID: 20920794 PMCID: PMC2978156 DOI: 10.1016/j.neuron.2010.09.002] [Citation(s) in RCA: 305] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2010] [Indexed: 12/16/2022]
Abstract
Fasting has been used to control epilepsy since antiquity, but the mechanism of coupling between metabolic state and excitatory neurotransmission remains unknown. Previous work has shown that the vesicular glutamate transporters (VGLUTs) required for exocytotic release of glutamate undergo an unusual form of regulation by Cl(-). Using functional reconstitution of the purified VGLUTs into proteoliposomes, we now show that Cl(-) acts as an allosteric activator, and the ketone bodies that increase with fasting inhibit glutamate release by competing with Cl(-) at the site of allosteric regulation. Consistent with these observations, acetoacetate reduced quantal size at hippocampal synapses and suppresses glutamate release and seizures evoked with 4-aminopyridine in the brain. The results indicate an unsuspected link between metabolic state and excitatory neurotransmission through anion-dependent regulation of VGLUT activity.
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MESH Headings
- 4-Aminopyridine/pharmacology
- Acetoacetates/pharmacology
- Animals
- Astrocytes/drug effects
- Astrocytes/physiology
- Behavior, Animal
- Cells, Cultured
- Chlorides/metabolism
- Chromatography, High Pressure Liquid/methods
- Disease Models, Animal
- Dopamine/metabolism
- Dose-Response Relationship, Drug
- Embryo, Mammalian
- Excitatory Postsynaptic Potentials/drug effects
- Exocytosis/drug effects
- Exocytosis/genetics
- Gene Expression Regulation
- Glutamic Acid/metabolism
- Hippocampus/cytology
- Humans
- In Vitro Techniques
- Ketone Bodies
- Membrane Potential, Mitochondrial/drug effects
- Membrane Potential, Mitochondrial/genetics
- Mice
- Mice, Inbred C57BL
- Microdialysis/methods
- Models, Biological
- Neurons/drug effects
- Neurons/metabolism
- Patch-Clamp Techniques/methods
- Potassium Channel Blockers/pharmacology
- Rats
- Seizures/chemically induced
- Seizures/physiopathology
- Synaptic Vesicles/metabolism
- Vesicular Glutamate Transport Protein 2/chemistry
- Vesicular Glutamate Transport Protein 2/genetics
- Vesicular Glutamate Transport Protein 2/metabolism
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Research Support, N.I.H., Extramural |
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Chalmers S, Nicholls DG. The relationship between free and total calcium concentrations in the matrix of liver and brain mitochondria. J Biol Chem 2003; 278:19062-70. [PMID: 12660243 DOI: 10.1074/jbc.m212661200] [Citation(s) in RCA: 298] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Three sequential phases of mitochondrial calcium accumulation can be distinguished: matrix dehydrogenase regulation, buffering of extramitochondrial free calcium, and finally activation of the permeability transition. Relationships between these phases, free and total matrix calcium concentration, and phosphate concentration are investigated in rat liver and brain mitochondria. Slow, continuous calcium infusion is employed to avoid transient bioenergetic consequences of bolus additions. Liver and brain mitochondria undergo permeability transitions at precise matrix calcium loads that are independent of infusion rate. Cytochrome c release precedes the permeability transition. Cyclosporin A enhances the loading capacity in the presence or absence of acetoacetate. A remarkably constant free matrix calcium concentration, in the range 1-5 microM as monitored by matrix-loaded fura2-FF, was observed when total matrix calcium was increased from 10 to at least 500 nmol of calcium/mg of protein. Increasing phosphate decreased both the free matrix calcium and the matrix calcium-loading capacity. Thus the permeability transition is not triggered by a critical matrix free calcium concentration. The rate of hydrogen peroxide detection by Amplex Red decreased during calcium infusion arguing against a role for oxidative stress in permeability pore activation in this model. A transition between a variable and buffered matrix free calcium concentration occurred at 10 nmol of total matrix calcium/mg protein. The solubility product of amorphous Ca3(PO4)2 is consistent with the observed matrix free calcium concentration, and the matrix pH is proposed to play the major role in maintaining the low matrix free calcium concentration.
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Espeseth AS, Felock P, Wolfe A, Witmer M, Grobler J, Anthony N, Egbertson M, Melamed JY, Young S, Hamill T, Cole JL, Hazuda DJ. HIV-1 integrase inhibitors that compete with the target DNA substrate define a unique strand transfer conformation for integrase. Proc Natl Acad Sci U S A 2000; 97:11244-9. [PMID: 11016953 PMCID: PMC17185 DOI: 10.1073/pnas.200139397] [Citation(s) in RCA: 255] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2000] [Indexed: 01/28/2023] Open
Abstract
Diketo acids such as L-731,988 are potent inhibitors of HIV-1 integrase that inhibit integration and viral replication in cells. These compounds exhibit the unique ability to inhibit the strand transfer activity of integrase in the absence of an effect on 3' end processing. To understand the reasons for this distinct inhibitory profile, we developed a scintillation proximity assay that permits analysis of radiolabeled inhibitor binding and integrase function. High-affinity binding of L-731,988 is shown to require the assembly of a specific complex on the HIV-1 long terminal repeat. The interaction of L-731,988 with the complex and the efficacy of L-731, 988 in strand transfer can be abrogated by the interaction with target substrates, suggesting competition between the inhibitor and the target DNA. The L-731,988 binding site and that of the target substrate are thus distinct from that of the donor substrate and are defined by a conformation of integrase that is only adopted after assembly with the viral end. These results elucidate the basis for diketo acid inhibition of strand transfer and have implications for integrase-directed HIV-1 drug discovery efforts.
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Denton RM, Randle PJ, Bridges BJ, Cooper RH, Kerbey AL, Pask HT, Severson DL, Stansbie D, Whitehouse S. Regulation of mammalian pyruvate dehydrogenase. Mol Cell Biochem 1975; 9:27-53. [PMID: 171557 DOI: 10.1007/bf01731731] [Citation(s) in RCA: 207] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In mammalian tissues, two types of regulation of the pyruvate dehydrogenase complex have been described: end product inhibition by acetyl CoA and NADH: and the interconversion of an inactive phosphorylated form and an active nonphosphorylated form by an ATP requiring kinase and a specific phosphatase. This article is largely concerned with the latter type of regulation of the complex in adipose tissue by insulin (and other hormones) and in heart muscle by lipid fuels. Effectors of the two interconverting enzymes include pyruvate and ADP which inhibit the kinase, acetoin which activates the kinase and Ca2+ and Mg2+ which both activate the phosphatase and inhibit the kinase. Evidence is presented that all components of the pyruvate dehydrogenase complex including the phosphatase and kinase are located within the inner mitochondrial membrane. Direct measurements of the matrix concentration of substrates and effectors is not possible by techniques presently available. This is the key problem in the identification of the mechansims involved in the alterations in pyruvate dehydrogenase activity observed in adipose tissue and muscle. A number of indirect approaches have been used and these are reviewed. Most hopeful is the recent finding in this laboratory that in both adipose tissue and heart muscle, differences in activity of pyruvate dehydrogenase in the intact tissue persist during preparation and subsequent incubation of mitochondria.
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Garland PB, Newsholme EA, Randle PJ. Regulation of glucose uptake by muscle. 9. Effects of fatty acids and ketone bodies, and of alloxan-diabetes and starvation, on pyruvate metabolism and on lactate-pyruvate and L-glycerol 3-phosphate-dihydroxyacetone phosphate concentration ratios in rat heart and rat diaphragm muscles. Biochem J 1964; 93:665-78. [PMID: 4284560 PMCID: PMC1214025 DOI: 10.1042/bj0930665] [Citation(s) in RCA: 190] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Jourdan F, Duveau A, Astic L, Holley A. Spatial distribution of [14C]2-deoxyglucose uptake in the olfactory bulbs of rats stimulated with two different odours. Brain Res 1980; 188:139-54. [PMID: 7370749 DOI: 10.1016/0006-8993(80)90563-6] [Citation(s) in RCA: 179] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The uptake of [14C]2-deoxy-D-glucose (2-DG) has been studied by autoradiography in the olfactory bulbs of control and odour-stimulated rats. The sites of highest 2-DG-uptake coincide very accurately with individual glomeruli. The other bulbar histological layers appear to be far less metabolically affected by the olfactory stimulation. The mapping of the glomerular activation has been compared in two groups of animals stimulated with two different odours. The patterns of selective glomerular 2-DG-uptake are rather similar within each group. They differ from one group to the other by the number and localization of the highly labelled glomeruli. It can be inferred from our observations that a few glomeruli are metabolically highly activated by a strong and pure odour stimulation. A correlation between the quality of the odour and the pattern of glomerular activation may be supposed but has to be confirmed with other compounds.
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Newsholme EA, Randle PJ. Regulation of glucose uptake by muscle. 7. Effects of fatty acids, ketone bodies and pyruvate, and of alloxan-diabetes, starvation, hypophysectomy and adrenalectomy, on the concentrations of hexose phosphates, nucleotides and inorganic phosphate in perfused rat heart. Biochem J 1964; 93:641-51. [PMID: 4220951 PMCID: PMC1214023 DOI: 10.1042/bj0930641] [Citation(s) in RCA: 155] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Pais GCG, Zhang X, Marchand C, Neamati N, Cowansage K, Svarovskaia ES, Pathak VK, Tang Y, Nicklaus M, Pommier Y, Burke TR. Structure activity of 3-aryl-1,3-diketo-containing compounds as HIV-1 integrase inhibitors. J Med Chem 2002; 45:3184-94. [PMID: 12109903 DOI: 10.1021/jm020037p] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The 4-aryl-2-hydroxy-4-oxo-2-butenoic acids and their isosteric tetrazoles are among an emerging class of aryl beta-diketo (ADK)-based agents which exhibit potent inhibition of HIV-1 integrase (IN)-catalyzed strand transfer (ST) processes, while having much reduced potencies against 3'-processing (3'-P) reactions. In the current study, L-708,906 (10e) and 5CITEP (13b), which are two examples of ADK inhibitors that have been reported by Merck and Shionogi pharmaceutical companies, served as model ADK leads. Structural variations to both the "left" and "right" sides of these molecules were made in order to examine effects on HIV-1 integrase inhibitory potencies. It was found that a variety of groups could be introduced onto the left side aryl ring with maintenance of good ST inhibitory potency. However, introduction of carboxylic acid-containing substituents onto the left side aryl ring enhanced 3'-P inhibitory potency and reduced selectivity toward ST reactions. Although both L-708,906 and 5CITEP show potent inhibition of IN in biochemical assays, there is a disparity of antiviral activity in cellular assays using HIV-1-infected cells. Neither 5CITEP nor any other of the indolyl-containing inhibitors exhibit significant antiviral effects in cellular systems. Alternatively, consistent with literature reports, L-708,906 does provide antiviral protection at low micromolar concentrations. Interestingly, several analogues of L-708,906 with varied substituents on the left side aryl ring, while having good inhibitory potencies against IN in extracellular assays, are not antiviral in whole-cell systems.
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Maizels EZ, Ruderman NB, Goodman MN, Lau D. Effect of acetoacetate on glucose metabolism in the soleus and extensor digitorum longus muscles of the rat. Biochem J 1977; 162:557-68. [PMID: 869905 PMCID: PMC1164638 DOI: 10.1042/bj1620557] [Citation(s) in RCA: 142] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
1. The effect of acetoacetate on glucose metabolism was compared in the soleus, a slow-twitch red muscle, and the extensor digitorum longus, a muscle composed of 50% fast-twitch red and 50% white fibres. 2. When incubated for 2h in a medium containing 5 mM-glucose and 0.1 unit of insulin/ml, rates of glucose uptake, lactate release and glucose oxidation in the soleus were 19.6, 18.6 and 1.47 micronmol/h per g respectively. Acetoacetate (1.7 mM) diminished all three rates by 25-50%; however, it increased glucose conversion into glycogen. In addition, it caused increases in tissue glucose, glucose 6-phosphate and fructose 6-phosphate, suggesting inhibition of phosphofructokinase. The concentrations of citrate, an inhibitor of phosphofructokinase, and of malate were also increased. 3. Rates of glucose uptake and lactate release in the extensor digitorum longus were 50-80% of those in the soleus. Acetoacetate caused moderate increases in tissue glucose 6-phosphate and possibly citrate, but it did not decrease glucose uptake or lactate release. 4. The rate of glycolysis in the soleus was approximately five times that previously observed in the perfused rat hindquarter, a muscle preparation in which acetoacetate inhibits glucose oxidation, but does not alter glucose uptake or glycolysis. A similar rate of glycolysis was observed when the soleus was incubated with a glucose-free medium. Under these conditions, tissue malate and the lactate/pyruvate ratio in the medium were decreased, and acetoacetate did not decrease lactate release or increase tissue citrate or glucose 6-phosphate. An intermediate rate of glycolysis, which was not decreased by acetoacetate, was observed when the soleus was incubated with glucose, but not insulin. 5. The data suggest that acetoacetate glucose inhibits uptake and glycolysis in red muscle under conditions that resemble mild to moderate exercise. They also suggest that the accumulation of citrate in these circumstances is linked to the rate of glycolysis, possibly through the generation of cytosolic NADH and malate formation.
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Shug A, Lerner E, Elson C, Shrago E. The inhibition of adenine nucleotide translocase activity by oleoyl CoA and its reversal in rat liver mitochondria. Biochem Biophys Res Commun 1971; 43:557-63. [PMID: 5563306 DOI: 10.1016/0006-291x(71)90650-4] [Citation(s) in RCA: 142] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Berger M, Hagg SA, Goodman MN, Ruderman NB. Glucose metabolism in perfused skeletal muscle. Effects of starvation, diabetes, fatty acids, acetoacetate, insulin and exercise on glucose uptake and disposition. Biochem J 1976; 158:191-202. [PMID: 136249 PMCID: PMC1163959 DOI: 10.1042/bj1580191] [Citation(s) in RCA: 142] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
1. The regulation of glucose uptake and disposition in skeletal muscle was studied in the isolated perfused rat hindquarter. 2. Insulin and exercise, induced by sciatic-nerve stimulation, enhanced glucose uptake about tenfold in fed and starved rats, but were without effect in rats with diabetic ketoacidosis. 3. At rest, the oxidation of lactate (0.44 mumol/min per 30 g muscle in fed rats) was decreased by 75% in both starved and diabetic rats, whereas the release of alanine and lactate (0.41 and 1.35 mumol/min per 30 g respectively in the fed state) was increased. Glycolysis, defined as the sum of lactate+alanine release and lactate oxidation, was not decreased in either starvation or diabetes. 4. In all groups, exercise tripled O2 consumption (from approximately 8 to approximately 25 mumol/min per 30 g of muscle) and increased the release and oxidation of lactate five- to ten-fold. The differences in lactate release between fed, starved and diabetic rats observed at rest were no longer apparent; however, lactate oxidation was still several times greater in the fed group. 5. Perfusion of the hindquarter of a fed rat with palmitate, octanoate or acetoacetate did not alter glucose uptake or lactate release in either resting or exercising muslce; however, lactate oxidation was significantly inhibited by acetoacetate, which also increased the intracellular concentration of acetyl-CoA. 6. The data suggest that neither that neither glycolysis nor the capacity for glucose transport are inhbitied in the perfused hindquarter during starvation or perfusion with fatty acids or ketone bodies. On the other hand, lactate oxidation is inhibited, suggesting diminished activity of pyruvate dehydrogenase. 7. Differences in the regulation of glucose metabolism in heart and skeletal muscle and the role of the glucose/fatty acid cycle in each tissue are discussed.
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Parish CR. Immune response to chemically modified flagellin. II. Evidence for a fundamental relationship between humoral and cell-mediated immunity. J Exp Med 1971; 134:21-47. [PMID: 5558070 PMCID: PMC2139030 DOI: 10.1084/jem.134.1.21] [Citation(s) in RCA: 133] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Flagellin (mol.wt. 40,000) from S. adelaide organisms and a series of acetoacetyl derivatives of flagellin were tested for their ability to induce humoral and cell-mediated immunity in adult rats. It was found that unmodified flagellin was an excellent inducer of antibody formation but a poor inducer of delayed-type hypersensitivity. In contrast, increasing acetoacetylation steadily destroyed the ability of flagellin to initiate antibody formation but enhanced the capacity of the molecule to induce flagellin-specific cell-mediated immunity and antibody tolerance. In fact, it appeared that in adult rats antibody formation and cell-mediated immunity may well be opposing immunological processes. Furthermore, the affinity of the acetoacetyl flagellins for anti-flagellin antibodies appeared to determine the type of immune response which predominated. High affinity antigen produced antibody formation whereas low affinity antigen induced cell-mediated immunity and antibody tolerance. The importance of affinity was further evidenced by the fact that a CNBr digest of flagellin induced humoral and cellular immune responses identical to an acetoacetylated flagellin of comparable antigenic activity. From these studies it was proposed that both humoral and cell-mediated immunity can be directed against the same antigenic determinants but that the specificity requirements for delayed hypersensitivity (and antibody tolerance) are less than those required for antibody formation. Some remarkable immunological features of the flagellin system were revealed. Flagellin induced comparable delayed-type hypersensitivity when injected in either saline or FCA. Furthermore, FCA only slightly enhanced the delayed responses induced by the acetoacetyl flagellins and in fact these preparations produced antibody tolerance whether injected in saline or adjuvant. Finally, in contrast to the adult tolerance induced by the acetoacetylated flagellins, which existed only at the antibody level, tolerance in neonatal rats existed at the level of both humoral and cell-mediated immunity. This finding is the first indication of a fundamental difference between neonatal and adult tolerance. The significance of these findings is discussed in the light of current immunological concepts and a hypothesis proposed to explain these phenomena.
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Abstract
1. The role of enhanced aerobic glycolysis in the transformation of rat thymocytes by concanavalin A has been investigated. Concanavalin A addition doubled [U-(14)C]glucose uptake by rat thymocytes over 3h and caused an equivalent increased incorporation into protein, lipids and RNA. A disproportionately large percentage of the extra glucose taken up was converted into lactate, but concanavalin A also caused a specific increase in pyruvate oxidation, leading to an increase in the percentage contribution of glucose to the respiratory fuel. 2. Acetoacetate metabolism, which was not affected by concanavalin A, strongly suppressed pyruvate oxidation in the presence of [U-(14)C]glucose, but did not prevent the concanavalin A-induced stimulation of this process. Glucose uptake was not affected by acetoacetate in the presence or absence of concanavalin A, but in each case acetoacetate increased the percentage of glucose uptake accounted for by lactate production. 3. [(3)H]Thymidine incorporation into DNA in concanavalin A-treated thymocyte cultures was sensitive to the glucose concentration in the medium in a biphasic manner. Very low concentrations of glucose (25mum) stimulated DNA synthesis half-maximally, but maximum [(3)H]thymidine incorporation was observed only when the glucose concentration was raised to 1mm. Lactate addition did not alter the sensitivity of [(3)H]-thymidine uptake to glucose, but inosine blocked the effect of added glucose and strongly inhibited DNA synthesis. 4. It is suggested that the major function of enhanced aerobic glycolysis in transforming lymphocytes is to maintain higher steady-state amounts of glycolytic intermediates to act as precursors for macromolecule synthesis.
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Thio LL, Wong M, Yamada KA. Ketone bodies do not directly alter excitatory or inhibitory hippocampal synaptic transmission. Neurology 2000; 54:325-31. [PMID: 10668691 DOI: 10.1212/wnl.54.2.325] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine the effect of the ketone bodies beta-hydroxybutyrate (betaHB) and acetoacetate (AA) on excitatory and inhibitory neurotransmission in the mammalian CNS. BACKGROUND The ketogenic diet is presumed to be an effective anticonvulsant regimen for some children with medically intractable seizures. However, its mechanism of action remains a mystery. According to one hypothesis, ketone bodies have anticonvulsant properties. METHODS The authors examined the effect of betaHB and AA on excitatory and inhibitory synaptic transmission in rat hippocampal-entorhinal cortex slices and cultured hippocampal neurons. In cultured neurons, their effect was also directly assayed on postsynaptic receptor properties. Finally, their ability to prevent spontaneous seizures was determined in a hippocampal-entorhinal cortex slice model. RESULTS betaHB and AA did not alter synaptic transmission in these models. CONCLUSIONS The anticonvulsant properties of the ketogenic diet do not result from a direct effect of ketone bodies on the primary voltage and ligand gated ion channels mediating excitatory or inhibitory neurotransmission in the hippocampus.
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Russell RR, Taegtmeyer H. Changes in citric acid cycle flux and anaplerosis antedate the functional decline in isolated rat hearts utilizing acetoacetate. J Clin Invest 1991; 87:384-90. [PMID: 1671390 PMCID: PMC295088 DOI: 10.1172/jci115008] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
To determine the temporal relationship between changes in contractile performance and flux through the citric acid cycle in hearts oxidizing acetoacetate, we perfused isolated working rat hearts with either glucose or acetoacetate (both 5 mM) and freeze-clamped the tissue at defined times. After 60 min of perfusion, hearts utilizing acetoacetate exhibited lower systolic and diastolic pressures and lower cardiac outputs. The oxidation of acetoacetate increased the tissue content of 2-oxoglutarate and glutamate and decreased the content of succinyl-CoA suggesting inhibition of citric acid cycle flux through 2-oxoglutarate dehydrogenase. Whereas hearts perfused with either acetoacetate or glucose were similar with respect to their function for the first 20 min, changes in tissue metabolites were already observed within 5 min of perfusion at near-physiological workloads. The addition of lactate or propionate, but not acetate, to hearts oxidizing acetoacetate improved contractile performance, although inhibition of 2-oxoglutarate dehydrogenase was probably not diminished. If lactate or propionate were added, malate and citrate accumulated indicating utilization of anaplerotic pathways for the citric acid cycle. We conclude that a decreased rate of flux through 2-oxoglutarate dehydrogenase in hearts oxidizing acetoacetate precedes, and may be responsible for, contractile failure and is not the result of decreased cardiac work. Further, anaplerosis play an important role in the maintenance of contractile function in hearts utilizing acetoacetate.
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Goodman MN, Berger M, Ruderman NB. Glucose metabolism in rat skeletal muscle at rest. Effect of starvation, diabetes, ketone bodies and free fatty acids. Diabetes 1974; 23:881-8. [PMID: 4279193 DOI: 10.2337/diab.23.11.881] [Citation(s) in RCA: 108] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The influence of starvation, diabetic ketoacidosis, ketone bodies and free fatty acids on glucose metabolism in resting skeletal muscle was studied in the isolated perfused rat hindquarter perparation and in intact rats. In the hindquarter preparation, the provision of 1.3 mM oleate, 1 mM octanoate or 2 mM acetoacetate did not alter the uptake of glucose in the presence of insulin. In contrast, glucose uptake in the presence of insulin was significantly depressed in hindquarters of rats with diabetic ketosis. In fed, fasted and diabetic rats the distribution space of glucose in skeletal muscle in vivo ranged between 15 to 20 per cent (extracellular space, 18 to 20 per cent), indicating that transport into the cell and not phosphorylation was rate-limiting for glucose uptake. The administration of glucose and insulin did not increase the glucose distribution space in fed or fasted rats; however, it caused a marked increase in tissue lactate in the fasted group, suggesting inhibition of pyruvate oxidation. The concentrations of hexose monophosphates in skeletal muscle freeze-clamped in vivo were very similar in the three groups, indicating phosphofructokinase was not inhibited in the fasted or diabetic rats. There were also no major differences in the concentrations of citrate, glycerolphosphate, ATP, ADP and AMP: the concentration of acetyl CoA was increased in both forty-eight hour fasted and diabetic rats and free CoA was diminished in the diabetic rats. Tissue glycogen waslower in fasted and diabetic than in fed rats. The data suggest that in resting skeletal muscle there is no inhibition of glucose metabolism by exogenous fatty acids and ketone bodies anaiagous to that which occurs in heart and diaphragm. The rate limiting step in glucose uptake appears to be its transport into the cell which is inhibited in rats with diabetic ketosis. Glucose metabolism at the level of pyruvate dehydrogenase may be inhibited in skeletal muscle during fasting and diabetes as a result of changes in the concentrations of acetyl CoA and CoA.
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Koçyiğit KB, Rollas S. Synthesis, characterization and evaluation of antituberculosis activity of some hydrazones. FARMACO (SOCIETA CHIMICA ITALIANA : 1989) 2002; 57:595-9. [PMID: 12164221 DOI: 10.1016/s0014-827x(02)01255-7] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Several new hydrazone derivatives were prepared by the reaction of some active hydrogen compounds with the diazonium salts of 4-amino-3,5-di/1,3,5-trimethylpyrazoles at 0-5 degrees C. Structures of the new substances were confirmed using UV, IR, 1H NMR, 13C NMR and EI-mass spectral data. In vitro antituberculosis activity of these compounds were tested on Mycobacterium tuberculosis H37Rv at 6.25 microg/ml. Both hydrazone products, ethyl 2-[(3,5-dimethylpyrazole-4-yl)hydrazono]-3-oxobutyrate (3d) and methyl 2-[(3,5-dimethylpyrazole-4-yl)hydrazono]4-methoxy-3-oxobutyrate (3e) showed 29 and 28% inhibition against M. tuberculosis, respectively.
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Massieu L, Haces ML, Montiel T, Hernández-Fonseca K. Acetoacetate protects hippocampal neurons against glutamate-mediated neuronal damage during glycolysis inhibition. Neuroscience 2003; 120:365-78. [PMID: 12890508 DOI: 10.1016/s0306-4522(03)00266-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Glucose is the main substrate that fulfills energy brain demands. However, in some circumstances, such as diabetes, starvation, during the suckling period and the ketogenic diet, brain uses the ketone bodies, acetoacetate and beta-hydroxybutyrate, as energy sources. Ketone body utilization in brain depends directly on its blood concentration, which is normally very low, but increases substantially during the conditions mentioned above. Glutamate neurotoxicity has been implicated in neurodegeneration associated with brain ischemia, hypoglycemia and cerebral trauma, conditions related to energy failure, and to elevation of glutamate extracellular levels in brain. In recent years substantial evidence favoring a close relation between glutamate neurotoxic potentiality and cellular energy levels, has been compiled. We have previously demonstrated that accumulation of extracellular glutamate after inhibition of its transporters, induces neuronal death in vivo during energy impairment induced by glycolysis inhibition. In the present study we have assessed the protective potentiality of the ketone body, acetoacetate, against glutamate-mediated neuronal damage in the hippocampus of rats chronically treated with the glycolysis inhibitor, iodoacetate, and in hippocampal cultured neurons exposed to a toxic concentration of iodoacetate. Results show that acetoacetate efficiently protects against glutamate neurotoxicity both in vivo and in vitro probably by a mechanism involving its role as an energy substrate.
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Comparative Study |
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Zhou S, Shao Y, Gao N, Deng Y, Qiao J, Ou H, Deng J. Effects of different algaecides on the photosynthetic capacity, cell integrity and microcystin-LR release of Microcystis aeruginosa. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 463-464:111-119. [PMID: 23792253 DOI: 10.1016/j.scitotenv.2013.05.064] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 05/12/2013] [Accepted: 05/13/2013] [Indexed: 06/02/2023]
Abstract
Bench scale tests were conducted to study the effects of four common algaecides, including copper sulfate, hydrogen peroxide, diuron and ethyl 2-methylacetoacetate (EMA) on the photosynthetic capacity, cell integrity and microcystin-LR (MC-LR) release of Microcystis aeruginosa. The release of potassium (K(+)) from cell membrane during algaecide exposure was also analyzed. The three typical photosynthetic parameters, including the effective quantum yield (Фe), photosynthetic efficiency (α) and maximal electron transport rate (rETRmax), were measured by a pulse amplitude modulated (PAM) fluorometry. Results showed that the photosynthetic capacity was all inhibited by the four algaecides, to different degrees, by limiting the energy capture in photosynthesis, and blocking the electron transfer chain in primary reaction. For example, at high diuron concentration (7.5 mg L(-1)), Фe, α and rETRmax decreased from 0.46 to 0.19 (p<0.01), from 0.20 to 0.01 (p<0.01) μmol electrons m(-2) s(-1)/μmol photons m(-2) s(-1), and from 160.7 to 0.1 (p<0.001) μmol m(-2) s(-1) compared with the control group after 96 h of exposure, respectively. Furthermore, the increase of algaecide dose could lead to the cell lysis, as well as release of intracellular MC-LR that enhanced the accumulation of extracellular MC-LR. The order of MC-LR release potential for the four algaecides was CuSO4>H2O2>diuron>EMA.
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Johnson AA, Marchand C, Pommier Y. HIV-1 integrase inhibitors: a decade of research and two drugs in clinical trial. Curr Top Med Chem 2004; 4:1059-77. [PMID: 15193139 DOI: 10.2174/1568026043388394] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
AIDS is currently treated with a combination therapy of reverse transcriptase and protease inhibitors. Recently, the FDA approved a drug targeting HIV-1 entry into cells. There are currently no FDA approved drugs targeting HIV-1 integrase, though many scientists and drug companies are actively in pursuit of clinically useful integrase inhibitors. The objective of this review is to provide an update on integrase inhibitors reported in the last two years, including two novel inhibitors in early clinical trials, recently developed hydroxylated aromatics, natural products, peptide, antibody and oligonucleotide inhibitors. Additionally, the proposed mechanism of diketo acid inhibition is reviewed.
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Review |
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Uehara Y, Engel T, Li Z, Goepfert C, Rust S, Zhou X, Langer C, Schachtrup C, Wiekowski J, Lorkowski S, Assmann G, von Eckardstein A. Polyunsaturated fatty acids and acetoacetate downregulate the expression of the ATP-binding cassette transporter A1. Diabetes 2002; 51:2922-8. [PMID: 12351428 DOI: 10.2337/diabetes.51.10.2922] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Low HDL cholesterol is a frequent cardiovascular risk factor in diabetes. Because of its pivotal role for the regulation of HDL plasma levels, we investigated in vivo and in vitro regulation of the ATP-binding cassette transporter A1 (ABCA1) by insulin and metabolites accumulating in diabetes. Compared with euglycemic control mice, ABCA1 gene expression was severely decreased in the liver and peritoneal macrophages of diabetic mice. Treatment with insulin restored this deficit. Incubation of cultivated HepG2 hepatocytes and RAW264.7 macrophages with unsaturated fatty acids or acetoacetate, but not with insulin, glucose, saturated fatty acids, or hydroxybutyrate, downregulated ABCA1 mRNA and protein. The suppressive effect of unsaturated fatty acids and acetoacetate became most obvious in cells stimulated with oxysterols or retinoic acid but was independent of the expression of the thereby regulated transcription factors liver-X-receptor alpha (LXRalpha) and retinoid-X-receptor alpha (RXRalpha), respectively. Unsaturated fatty acids and acetoacetate also reduced ABCA1 promotor activity in RAW264.7 macrophages that were transfected with a 968-bp ABCA1 promotor/luciferase gene construct. As the functional consequence, unsaturated fatty acids and acetoacetate inhibited cholesterol efflux from macrophages. Downregulation of ABCA1 by unsaturated fatty acids and acetoacetate may contribute to low HDL cholesterol and increased cardiovascular risk of diabetic patients.
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